Cellular wheel and method for the production thereof

ABSTRACT

A cellular wheel made of metal comprises an outer sleeve located symmetrically to a rotational axis and an inner sleeve. The annular space between the outer sleeve and inner sleeve is divided by cell wall parts, which are oriented in parallel to the rotational axis and delimited by cell edges, into a plurality of rotation-symmetrically arranged cells, wherein the cell edges are located on intersecting lines of cylinder lateral surfaces with rotation-symmetrically arranged axial planes, said surfaces being arranged concentrically to the rotational axis. The outer sleeve and inner sleeve delimit a cell structure, in which cell edges, which delimit a cell wall part in each case, are concurrently located in pairs on adjoining cylinder lateral surfaces and on adjoining axial planes. With each cell edge located on two adjoining axial planes of adjoining cylinder lateral surfaces, each cell edge on a cylinder lateral surface delimits two cell walls.

TECHNICAL FIELD

The present invention relates to a cellular wheel made of metal,comprising a cylindrical outer sleeve located symmetrically to arotational axis and a cylindrical inner sleeve located concentrically tothe outer sleeve, wherein the space between the outer sleeve and theinner sleeve is divided into a multiplicity of rotation-symmetricallyarranged cells by cell wall parts delimited by cell edges orientedparallel to the rotational axis, which cell edges lie withrotation-symmetrically arranged axial planes on lines of intersection ofcylinder shell surfaces arranged concentrically to the rotational axis.A method suitable for producing the cellular wheel also lies within thescope of the invention.

PRIOR ART

For some years, the process of downsizing has been one of the key issuesin the design of new, supercharged engines. With downsizing, the fuelconsumption and thus the exhaust emissions of a vehicle can be reduced.These aims are nowadays becoming increasingly important, since the highenergy consumption by fossil fuels contributes strongly to air pollutionand increasingly strict legislative measures are forcing automobilemanufacturers to take action. By downsizing, the substitution of ahigh-volume engine by a reduced-capacity engine is understood. In thisway, the engine power should be maintained at a constant rate bycharging the engine. The aim is to achieve the same output values withlow-volume engines as with equally powerful naturally aspirated engines.New insights in the field of downsizing have shown that, particularly invery small Otto engines with a cubic capacity of 1 liter or less, thebest results can be obtained with pressure wave supercharging.

In a pressure wave supercharger, the rotor is configured as a cellularwheel and is enclosed by an air and exhaust housing having a commoncasing. The development of modern pressure wave superchargers forsupercharging small engines leads to cellular wheels having a diameterin the order of magnitude of 100 mm or less. In order to obtain amaximum cell volume and also reduce the weight, cell wall thicknesses of0.2 mm or less are aimed for. Given the high exhaust inlet temperaturesof around 1000° C., virtually only high-temperature steels can beconsidered as materials for the cellular wheel. The production ofdimensionally stable and high-precision cellular wheels with lowcellular wall thickness is today barely possible, or else is associatedwith considerable additional costs.

It has already been proposed to form the chambers of a cellular wheelfrom aligned and partially overlapping, Z-shaped profiles. Theproduction of such a cellular wheel is associated, however, with hightime expenditure. Added to this is the fact that the alignment andpositionally accurate fixing of Z-profiles is barely practicable with aprecision sufficient to meet the required tolerances.

It has already been proposed to produce a cellular wheel from a solidbody by erosion of the individual cells. With this method, it is notpossible, however, to achieve cell wall thicknesses of 0.2 mm. A furtherfundamental drawback of the erosion method is constituted by the highmaterial and machining costs associated therewith.

From EP-A-1 375 859, a cellular wheel of the type stated in theintroduction is known. The cellular wheel comprises an outer sleeve, aninner sleeve located concentrically to the outer sleeve and anintermediate sleeve arranged between the outer sleeve and the innersleeve concentrically to these same. Between the outer sleeve and theintermediate sleeve and between the intermediate sleeve and the innersleeve are arranged blades oriented radially to the rotational axis. Theindividual cells are delimited by two adjacent blades and adjacentsleeves. In load tests under practical conditions, it has been shownthat, particularly with cell wall thicknesses of 0.5. mm or less, atorsion of the sleeves and a vibration of the blades occur. Thisunstable behavior leads after a short while to failure of the cellularwheel.

REPRESENTATION OF THE INVENTION

The object of the invention is to provide a cellular wheel of the typestated in the introduction, which has a higher rigidity than cellularwheels according to the prior art, given comparable cell wall thickness.Moreover, the cellular wheel is designed to be able to be produced in asimple and cost-effective manner with the required precision, whileavoiding the drawbacks of the prior art. A further aim of the inventionis to provide a dimensionally stable, lightweight cellular wheel for usein a pressure wave supercharger for supercharging internal combustionengines, in particular for supercharging small Otto engines having acubic capacity in the order of magnitude of 1 liter or less. A stillfurther aim of the invention is to provide a method for thecost-effective production of dimensionally stable and high-precisioncellular wheels having a cell wall thickness of 0.4 mm or less.

In a cellular wheel of the type stated in the introduction, theinventive solution of the object is achieved by the fact that the outersleeve and the inner sleeve delimit a cell structure constructed from anetwork formed in cross section in mesh-like arrangement from connectedcell wall parts, in which cell structure cell edges, which in pairsrespectively delimit a cell wall part, lie simultaneously on adjacentcylinder shell surfaces and on adjacent axial planes, wherein each celledge on a cylinder shell surface, with each of the cell edges lying ontwo adjacent axial planes of an adjacent cylinder shell surface,respectively delimits two cell wall parts.

By virtue of the cell structure which is used according to theinvention, the cellular wheel has a substantially higher rigidity thanthe known cellular wheels. Moreover, the absence of intermediate sleevesleads, in addition to a considerable weight reduction, to a stronglyincreased passage cross section.

The cell structure preferably comprises three or four cylinder shellsurfaces, though cellular wheels having more than four cylinder shellsurfaces are also conceivable.

In a particularly preferred, cost-effective method for producing thecellular wheel according to the invention, the cell structure is formed,based on the industrial production of honeycomb structures, bystretching of blade assemblies made up of blades connected locally atdifferent points.

The method is distinguished by the following steps to be executed insequence:

-   -   (a) provision of a predefined number of blades having a length        corresponding to the length of the cellular wheel and a width        appropriately tailored to the predefined thickness of the        annular space between the outer sleeve and the inner sleeve;    -   (b) paired welding together of the blades in the longitudinal        direction at predefined points to form a blade assembly, with        the formation of the cell edges;    -   (c) stretching of the blade assembly in a direction        perpendicular to the plane of the blades and of the stretched        blade assembly to form the annular cell structure;    -   (d) connection of the two terminal blades of the stretched and        bent blade assembly along corresponding cell edges;    -   (e) sliding of the inner sleeve into the annular cell structure        and sliding of the outer sleeve onto the annular cell structure;    -   (f) connection of the outer sleeve and inner sleeve to the blade        edges.

The connection of the two terminal blades of the stretched and bentblade assembly along corresponding cell edges, and the connection of theouter sleeve and inner sleeve to the blade edges, is preferably carriedout by welding together the parts by means of a laser beam or electronbeam.

A further preferred method for producing the cellular wheel according tothe invention is distinguished by the following steps to be executed insequence:

-   -   (a) provision of a predefined number of blades having a length        corresponding to the length of the cellular wheel and a width        appropriately tailored to the predefined thickness of the        annular space between the outer sleeve and the inner sleeve;    -   (b) shaping of the blades in accordance with their definitive        shape predefined by the annular cell structure and, if        necessary, connection of blade pairs to form individual cells;    -   (c) placement of the shaped blades or the cells at predefined        points in a predefined number on the outer side of the inner        sleeve, and connection of the blades or the cells one to another        to form the annular cell structure, and to the inner sleeve;    -   (d) sliding of the outer sleeve onto the annular cell structure;    -   (f) connection of the outer sleeve and inner sleeve to the blade        edges.

The connection of the blade pairs to form individual cells, and theconnection of the blades or the cells one to another to form the annularcell structure, and to the inner sleeve, is preferably carried out bywelding together the parts by means of a laser beam or electron beam.

The cellular wheel produced with the method according to the inventionis preferably used in a pressure wave supercharger for supercharginginternal combustion engines, in particular Otto engines having a cubiccapacity of 1 liter or less.

BRIEF DESCRIPTION OF THE DRAWING

Further advantages, features and details of the invention emerge fromthe following description of preferred illustrative embodiments and withreference to the drawing, which serves merely for illustrative purposesand should not be construed restrictively. The drawing showsschematically in

FIG. 1 a side view of a cellular wheel for a pressure wave supercharger;

FIG. 2 an oblique view of the front face of the cellular wheel of FIG.1;

FIG. 3 a section perpendicular to the rotational axis of the cellularwheel of FIG. 1 along the line I-I;

FIG. 4 a side view of a variant of the cellular wheel of FIG. 1;

FIG. 5 an oblique view of the front face of the cellular wheel of FIG.4;

FIG. 6 a section perpendicular to the rotational axis of the cellularwheel of FIG. 4 along the line II-II;

FIG. 7 a top view of a welded-together blade assembly for the productionof the cellular wheel of FIG. 3;

FIG. 8 a cross section through the blade assembly of FIG. 7 along theline III-III;

FIG. 9 a detail from the blade assembly of FIG. 8 following stretchingand bending into the cell structure, welded to the outer and innersleeve;

FIG. 10 a welding variant of the blade assembly of FIG. 7;

FIG. 11 an oblique view of a cellular wheel produced from the bladeassembly of FIG. 7;

FIG. 12 the blade assembly of FIG. 13 having the dimensions of the bladeassembly of FIG. 8 following stretching and bending into the cellstructure, welded to the outer and inner sleeve;

FIG. 13 a top view of a welded-together blade assembly for theproduction of the cellular wheel of FIG. 6;

FIG. 14 a cross section through the blade assembly of FIG. 13 along theline IV-IV;

FIG. 15 a detail from the blade assembly of FIG. 13 following stretchingand bending into the cell structure, welded to the outer and innersleeve;

FIG. 16 an oblique view of a cellular wheel produced from the bladeassembly of FIG. 13;

FIG. 17 an oblique view of an inner sleeve of a cellular wheel inaccordance with FIG. 3, with a part comprising mounted and joinedblades;

FIG. 18 a section through a sub-region of the arrangement of FIG. 17 atright angles to the cellular wheel axis, in enlarged representation;

FIG. 19 a longitudinal section through the arrangement of FIG. 17 withinserted tool and slid-on outer sleeve;

FIG. 20 a cross section through a part of the arrangement of FIG. 19along the line B-B, in enlarged representation;

FIG. 21 an oblique view of the arrangement of FIG. 19;

FIG. 22 a section through the arrangement of FIG. 21 at right angles tothe cellular wheel axis;

FIG. 23 an enlarged detail of the region X of FIG. 22;

FIG. 24 an oblique view of an inner sleeve of a cellular wheel inaccordance with FIG. 6, with a part comprising placed and joined blades;

FIG. 25 a section through a sub-region of the arrangement of FIG. 24 atright angles to the cellular wheel axis, in enlarged representation;

FIG. 26 a longitudinal section through the arrangement of FIG. 24 withinserted tool and slid-on outer sleeve;

FIG. 27 a cross section through a part of the arrangement of FIG. 26along the line B-B, in enlarged representation;

FIG. 28 an oblique view of the arrangement of FIG. 26;

FIG. 29 a section through the arrangement of FIG. 28 at right angles tothe cellular wheel axis;

FIG. 30 an enlarged detail of the region Y of FIG. 29.

DESCRIPTION OF PREFERRED EMBODIMENTS

A cellular wheel 10, shown in FIGS. 1 to 3 and 4 to 6, of a pressurewave supercharger (not represented in the drawing) consists of acylindrical outer sleeve 12 located symmetrically to a rotational axis yof the cellular wheel 10 and a cylindrical inner sleeve 14 locatedconcentrically to the outer sleeve 12. The outer sleeve 12 and the innersleeve 14 delimit a cell structure 17 consisting of a network formed incross section in mesh-like arrangement from connected cell wall parts19. The annular space between the outer sleeve 12 and the inner sleeve14 is divided into a multiplicity of rotation-symmetrically arrangedcells 22, 22′, 22″, 22 a, 22 b by cell wall parts 19 delimited by celledges 20 oriented parallel to the rotational axis y. The cell edges 20lie on lines of intersection of cylinder shell surfaces 18 a, 18 b, 18 b1, 18 b 2, 18 c, arranged concentrically to the rotational axis y, withrotation-symmetrically arranged axial planes 21. The cell edges 20,which respectively delimit a cell wall part 19, lie simultaneously onadjacent cylinder shell surfaces 18 a, 18 b, 18 b 1, 18 b 2, 18 c and onadjacent axial planes 21. Each cell edge 20 on a cylinder shell surface18 a, 18 b, 18 b 1, 18 b 2, 18 c delimits, with each of the cell edges20 lying on two adjacent axial planes of an adjacent cylinder shellsurface 18 a, 18 b, 18 b 1, 18 b 2, 18 c, respectively two further cellwall parts 19. Half of the lines of intersection of the cylinder shellsurfaces 18 a, 18 b, 18 b 1, 18 b 2, 18 c with the axial planes 21 areoccupied by cell edges 20, an unoccupied interface being respectivelylocated between adjacent cell edges 20 on the cylinder shell surfaces 18a, 18 b, 18 b 1, 18 b 2, 18 c and between adjacent cell edges 20 on theaxial planes 21. This arrangement of the cell edges 20 and theaforementioned condition that the cell edges 20, which in pairsrespectively delimit a cell wall part 19, lie simultaneously on adjacentcylinder shell surfaces 18 a, 18 b, 18 b 1, 18 b 2, 18 c and on adjacentaxial planes 21, produces in the cross section of the cellular wheel 10an extensive pattern of deltoids, which form the cross section of theindividual cells 22, 22 a, 22 b. In the finished cellular wheel, theannular cell structure 17 is delimited by the inner sleeve 14 and theouter sleeve 12. In this way, the intermediate spaces of adjacent cellsof deltoid cross section and the outer and inner sleeves 12, 14 giverise to further cells 22′, 22″ of triangular cross section.

In the cellular wheel 10 shown in FIGS. 1 to 3, the cell edges of theannular cell structure lie on points of intersection of 72 rotationallysymmetric axial planes 21 with 3 cylinder shell surfaces 18 a, 18 b, 18c, wherein, in the finished cellular wheel 10, the outer and the innercylinder shell surface 18 a, 18 c coincide with the inner wall of theouter sleeve 12 or of the inner sleeve 14. 36 cells 22 of deltoid crosssection and 2×36 cells 22′, 22″ of triangular cross section are thusobtained. The cell structure 17 has a rotational symmetry with respectto the rotational or cellular wheel axis y with an angle of rotation of360°/36=10°.

In the cellular wheel 10 shown in FIGS. 4 to 6, the cell edges of theannular cell structure lie on points of intersection of 72 rotationallysymmetric axial planes 21 with 4 cylinder shell surfaces 18 a, 18 b 1,18 b 2, 18 c, wherein in the finished cellular wheel 10 the outer andthe inner cylinder shell surface 18 a, 18 c coincide with the inner wallof the outer sleeve 12 or the inner sleeve 14. 2×36 cells 22 a, 22 b ofdeltoid cross section and 2×36 cells 22′, 22″ of triangular crosssection are thus obtained. The cell structure 17 has a rotationalsymmetry with respect to the rotational or cellular wheel axis y with anangle of rotation of 360°/36=10°.

The cellular wheel 10 represented by way of example in FIGS. 1 to 3 and4 to 6 and having a diameter D and a length L of, for example, in eachcase 100 mm, has respectively 108 and 144 cells in total. The outersleeve 12, the inner sleeve 14 and the cell wall parts have a standardwall thickness of, for example, 0.4 mm and consist of a highly heatresistant metallic material, for example Inconel 2.4856. The said partshave in the direction of the rotational axis y a same length Lcommensurate with the length of the cellular wheel 10 and extend betweentwo front faces of the cellular wheel 10 which stand perpendicular tothe rotational axis y. In the region of the two front faces are arrangedprofiles 24 of a labyrinth seal, which profiles encircle the outersleeve 12. The counter profiles to the profiles 24, which counterprofiles are necessary to the formation of the labyrinth seal, are foundon the inner wall of a cellular wheel housing (not represented in thedrawing) provided to accommodate the cellular wheel 10.

The production of a cellular wheel is explained in greater detail in thefollowing description of illustrative embodiments.

As can be seen from FIGS. 7 to 11, in a first production methodrectangular blades 16 of a length l and a width b are placedindividually one after the other congruently one upon the other,wherein, prior to each mounting of a further blade 16, respectively thetwo topmost blades 16 are welded together at predetermined points bymeans of a laser beam guided parallel to the longitudinal direction ofthe blades 16.

The blades 16 are lamellar, flat sheet-metal parts and are usually cutto the predefined length from a sheet-metal strip which is present inroll form.

The length 1 of the blades corresponds to the length L of the cellularwheel 10. The width b of the blades 16 or of the blade assembly 26 isgreater than the width or thickness B of the annular space or of theannular cell structure 17 between the outer sleeve 12 and the innersleeve 14 and allows for the decrease in width b of the blade assembly26 which occurs when the blade assembly 26 is subsequently stretched andbent into the cell structure 17.

For the formation of the cell structure 17 represented in FIG. 3, 72blades 16 in total are alternately welded together in the region of thetwo longitudinal edges 16k and in the longitudinal middle 16m over thetotal length 1, so that finally an assembly 26 of 72 welded-togetherblades 16 is formed. The assembly 26 of welded-together blades 16 isthen stretched in a direction z perpendicular to the plane of the blades16 and bent into the annular cell structure 17 until the first and thelast blade 16 of the assembly 26 touch. In this position, the twoterminal blades 16 of the assembly are welded together along theirlongitudinal middles 16 m.

In a next step, the outer sleeve 12 and the inner sleeve 14 in the formof tubular sleeves are slid on or in from a front face. Prior to theperformance of the welding operation, the cell walls of the annularlybent cell structure 17 are fixed in the predefined angular position in apositionally accurate manner by means of frontally inserted tools.Following the positioning of the outer sleeve 12 and the inner sleeve14, the longitudinal edges 16 k of the welded-together blade pairs 16are welded to the outer sleeve 12 or the inner sleeve 14 through theouter sleeve 12 or the inner sleeve 14 by means of a laser beam guidedalong each longitudinal edge 16 k (FIG. 9 and FIGS. 19 to 23).

For the formation of the cell structure 17 represented in FIG. 6, 72blades 16 in total are alternately welded together in the region of afirst longitudinal edge 16 k, as well as between the longitudinal middleand the second longitudinal edge 16 k and in the region of the secondlongitudinal edge 16 k, as well as between the longitudinal middle andthe first longitudinal edge 16 k over the total length l, so thatfinally an assembly 26 of 72 welded-together blades 16 is formed. Theassembly 26 of the welded-together blades 16 is then stretched in adirection z perpendicular to the plane of the blades 16 and bent intothe annular cell structure 17 until the first and the last blade 16 ofthe assembly 26 touch. In this position, the two terminal blades 16 ofthe assembly are welded together along corresponding edges.

In a next step, the outer sleeve 12 and the inner sleeve 14 in the formof tubular sleeves are slid on or in from a front face. Prior to theperformance of the welding operation, the cell walls of the annularlybent cell structure 17 are fixed in the predefined angular position in apositionally accurate manner by means of frontally inserted tools 34.Following the positioning of the outer sleeve 12 and the inner sleeve14, the longitudinal edges 16 k of the welded-together blade pairs 16are welded to the outer sleeve 12 or the inner sleeve 14 through theouter sleeve 12 or the inner sleeve 14 by means of a laser beam guidedalong each longitudinal edge 16 k (FIG. 15 and FIGS. 26 to 30).

A comparison of FIGS. 9 and 12 shows that cell structures of differentcell number according to FIGS. 3 and 6 can be installed in an annularspace of predefined dimensions between the outer and inner sleeve.

In the paired welding of the blades 16 to form the blade assembly 26,all weld seams can be made with a laser beam guided perpendicular to theplane of the blades 16 (FIG. 8 and FIG. 13). In a variant shown in FIG.10, the longitudinal edges 16 k are welded in pairs with a laser beamguided laterally parallel to the plane of the blades 16.

FIGS. 17 and 18 and FIGS. 24 and 25 show, as a variant of theabove-described production of a cellular wheel 10 according to FIG. 3 orFIG. 6, the furnishing of a prefabricated inner sleeve 14 or flangedsleeve 15 with individual blades 16 which have been preformed into theirdefinitive shape predefined by the annular cell structure 17, or withsuch blades which have been welded in pairs to form cells 22 or 22 a, 22b. The fundamental difference to the previously described productiontype lies in the fact that a previously produced inner sleeve 14 issuitably equipped. The joining of the individual blades 16 or cells 22or 22 a, 22 b one to another is effected from outside by means of alaser beam 30 guided perpendicular to the rotational axis y along thebutt edge. The welding of the individual blades 16 or cells 22 or 22 a,22 b to the inner sleeve 14 can be effected from outside by means of alaser beam 30′ guided at an angle to the corresponding axial plane 21along the butt edge, with the formation of a fillet weld, or from withinthe inner sleeve 14 by means of a laser beam 30″ guided perpendicular tothe rotational axis y along the butt edge, with the formation of a blindweld. The welding of the last cell to the inner sleeve is in any eventeffected, however, from within the inner sleeve 14. The inner sleeve 14can be a seamless sleeve, or a sheet-metal strip which has been bentinto a tubular sleeve and has been welded along a butt edge, with theformation of a longitudinal weld seam.

As can be seen from FIG. 17 or 24, the inner sleeve 14 which is equippedwith blades 16 welded in pairs to form cells 22 or 22 a, 22 b isdirectly connected to a drive shaft 13, i.e. a flanged sleeve can herebe dispensed with, or the inner sleeve 14 is slid onto a flanged sleeve15 already prior to being equipped with blades.

The connection of the inner sleeve 14 to the flanged sleeve 15 can beeffected, for instance, by welding together the end edges of the innersleeve 14 and the flanged sleeve 15 by means of laser beams 30 (notrepresented in the drawing).

As shown in FIGS. 19 to 23 for the production of a cellular wheelaccording to FIG. 3 and in FIGS. 26 to 30 for the production of acellular wheel according to FIG. 6, the blades 16 or cells 22 alreadywelded to the inner sleeve 14 are fixed in a predefined angular positionby means of frontally inserted tools 34. After the outer sleeve 12 hasbeen slid on, it is welded by means of laser beams 30, via a blind weld,to the free end edges of the underlying blades 16 or cells 22 or 22 a,22 b (FIGS. 22 and 23 or FIGS. 29 and 30).

REFERENCE SYMBOL LIST

10 cellular wheel

12 outer sleeve

13 drive shaft

14 inner sleeve

15 flanged sleeve

16 blades

17 cell structure

18 a,18 b,18 c cylinder shell surface

19 cell wall part

20 cell edges

21 axial plane

22,22 a,22 b,22′,22″ cells

24 labyrinth cell part

26 blade assembly

30,30′,30″ laser beam

34 tool

y rotational axis

1. A cellular wheel made of metal, comprising: a cylindrical outersleeve located symmetrically with respect to a rotational axis (y), anda cylindrical inner sleeve located concentrically with respect to theouter sleeve, wherein an annular space between the outer sleeve and theinner sleeve is divided into a multiplicity of rotation-symmetricallyarranged cells by cell wall parts delimited by cell edges orientedparallel to the rotational axis (y), which cell edges lie withrotation-symmetrically arranged axial planes on lines of intersection ofcylinder shell surfaces arranged concentrically to the rotational axis(y), wherein the outer sleeve and the inner sleeve delimit a cellstructure constructed from a network formed in cross section inmesh-like arrangement from connected cell wall parts, in which cellstructure cell edges, which in pairs respectively delimit a cell wallpart, lie simultaneously on adjacent cylinder shell surfaces and onadjacent axial planes, and wherein each cell edge on a cylinder shellsurface, with each of the cell edges lying on two adjacent axial planesof an adjacent cylinder shell surface, respectively delimits two cellwall parts.
 2. The cellular wheel as claimed in claim 1, wherein thecell structure comprises three cylinder shell surfaces.
 3. The cellularwheel as claimed in claim 1, wherein the cell structure comprises fourcylinder shell surfaces.
 4. The cellular wheel as claimed in claim 1,wherein the cell structure comprises more than four cylinder shellsurfaces.
 5. The cellular wheel as claimed in claim 1, wherein the wallthickness of the materials used to produce the cellular wheel measures0.4 mm or less.
 6. A method for producing from metal a cellular wheel,comprising: a cylindrical outer sleeve located symmetrically withrespect to a rotational axis (y), and a cylindrical inner sleeve locatedconcentrically with respect to the outer sleeve, wherein an annularspace between the outer sleeve and the inner sleeve is divided into amultiplicity of rotation-symmetrically arranged cells by cell wall partsdelimited by cell edges oriented parallel to the rotational axis (y),which cell edges lie with rotation-symmetrically arranged axial planeson lines of intersection of cylinder shell surfaces arrangedconcentrically to the rotational axis (y), wherein the method comprisesthe following steps to be executed in sequence; (a) provision of apredefined number of blades having a length (l) corresponding to thelength (L) of the cellular wheel and a width (b) appropriately tailoredto the predefined thickness (B) of the annular space between the outersleeve and the inner sleeve; (b) paired welding together of the bladesin the longitudinal direction at predefined points to form a bladeassembly, with the formation of the cell edges; (c) stretching of theblade assembly in a direction (z) perpendicular to the plane of theblades and of the stretched blade assembly to form the annular cellstructure; (d) connection of the two terminal blades of the stretchedand bent blade assembly along corresponding cell edges; (e) sliding ofthe inner sleeve into the annular cell structure and sliding of theouter sleeve onto the annular cell structure; (f) connection of theouter sleeve and inner sleeve to the blade edges.
 7. The method asclaimed in claim 6, wherein the connection of the two terminal blades ofthe stretched and bent blade assembly along corresponding cell edges andthe connection of the outer sleeve and inner sleeve to the blade edges,is carried out by welding together the parts by means of a laser beam orelectron beam.
 8. A method for producing from metal a cellular wheel,comprising: a cylindrical outer sleeve located symmetrically withrespect to a rotational axis (y), and a cylindrical inner sleeve locatedconcentrically with respect to the outer sleeve, wherein an annularspace between the outer sleeve and the inner sleeve is divided into amultiplicity of rotation-symmetrically arranged cells by cell wall partsdelimited by cell edges oriented parallel to the rotational axis (y),which cell edges lie with rotation-symmetrically arranged axial planeson lines of intersection of cylinder shell surfaces arrangedconcentrically to the rotational axis (y), wherein the method comprisesthe following the steps to be executed in sequence (a) provision of apredefined number of blades having a length (l) corresponding to thelength (L) of the cellular wheel and a width (b) appropriately tailoredto the predefined thickness (B) of the annular space between the outersleeve and the inner sleeve; (b) shaping of the blades in accordancewith their definitive shape predefined by the annular cell structureand, if necessary, connection of blade pairs to form individual cells;(c) placement of the shaped blades or the cells at predefined points ina predefined number on the outer side of the inner sleeve, andconnection of the blades or the cells one to another to form the annularcell structure and to the inner sleeve; (d) sliding of the outer sleeveonto the annular cell structure; (e) connection of the outer sleeve andinner sleeve to the blade edges.
 9. A method as claimed in claim 8,characterized in that wherein the connection of the blade pairs to formindividual cells, and the connection of the blades or the cells one toanother to form the annular cell structure, and to the inner sleeve, iscarried out by welding together the parts by means of a laser beam orelectron beam.
 10. The use of a cellular wheel as claimed in claim 1 ina pressure wave supercharger for supercharging internal combustionengines.
 11. The use of a cellular wheel as claimed in claim 2 in apressure wave supercharger for supercharging internal combustionengines.
 12. The use of a cellular wheel as claimed in claim 3 in apressure wave supercharger for supercharging internal combustionengines.
 13. The use of a cellular wheel as claimed in claim 4 in apressure wave supercharger for supercharging internal combustionengines.
 14. The use of a cellular wheel as claimed in claim 5 in apressure wave supercharger for supercharging internal combustionengines.